A BIRD’S VIEW ON PHARMACOLOGICAL EVALUATION OF TRANSITION METAL (II) COMPLEXES

A novel bioactive Cu(II), Ni(II) and VO(II) complexes have been synthesized with newly synthesized Schiff base(4, 4′- Bis- [1-ethyl-2-(2-mercapto-phenylimino)-butylideneamino]-biphenyl-3, 3′-diol) derived from 3, 3′- dihydroxybenzidine, Benzil and 2-aminothiophenol. The elemental analyses of the complexes are confined to the stoichiometry of the type M2L [M = Cu(II), Ni(II) and VO(II)] respectively, where L is Schiff base ligand. Structures have been proposed from elemental analyses, IR, electronic, 1H NMR, ESR spectral data and magnetic studies. The measured low molar conductance values in DMF indicate that the complexes are non-electrolytes. Spectroscopic studies suggest coordination occurs through azomethine nitrogen, oxygen and sulphur of the ligand with the metal ions. The cleavage products of the complexes analyzed by neutral agarose gel electrophoresis indicated that the interaction of the metal complexes with supercoiled plasmid DNA yielded linear, nicked or degraded DNA. The findings suggest that Cu(II) and VO(II) complexes with potent nucleolytic activity is a good nuclease substitute in the presence of cooxidant. The binding of these Cu(II) complex to DNA has been investigated by viscosity measurements. The experiments indicate that all the compounds can bind to DNA through an intercalative mode. In addition, the antioxidative activity was also determined. The antioxidative activity of the ligand and its complexes demonstrates that, compared to the ligand, the complexes exhibit higher scavenging activity. The Schiff base and its complexes have been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Klebsilla pneumonia, Bacillus subtilis and Salmonella typhi) and antifungal (Aspergillus niger, Aspergillus flavus, Aspergillus fumigates) activities.